Dell EqualLogic PS6100 series Configuration Manual page 64

Replication
Traditional replication
consideration
Network Replication requires that the network
Requirements connection between the primary and
secondary groups must be able to handle
the load of the data transfer and complete
the replication in a timely manner.
Snapshots Replication is functionally similar to
snapshots, creating point-in-time copies of
the volume. If the "keep failback" option is
enabled, the group creates a "failback
snapshot" on the primary group every time
a replica is created. This allows for "fast
failback" capabilities.
In addition, you can schedule the creation
of snapshots, or create them on demand,
just as you would with any other volume.
See About SyncRep and Snapshots on page
126 for more information.
Scheduling Replication operations can be scheduled
using the same mechanism used for
scheduling snapshots.
Pool Space The primary group must have enough
Requirements space for the volume reserve and local
replication reserve, in addition to any
snapshot reserve.
The secondary group must have enough
free space delegated to the primary group
for the volume reserve and the replicas that
record changes to the volume's data over
time.
March 2013 Dell EqualLogic Configuration Guide v14.1
SyncRep
Because writes are not
acknowledged until they are written
to both the SyncActive and
SyncAlternate pools, SyncRep is
sensitive to network latency.
The network must be able to handle
the load of the data transfer from the
SyncActive pool to the SyncAlternate
pool and complete the replication in
a timely manner, or application
performance may suffer.
SyncRep creates snapshots of the
volume whenever the SyncActive and
SyncAlternate pools are switched.
Replication between the SyncActive
and SyncAlternate pools is
continuous. Therefore there is no
need or mechanism to schedule
SyncRep.
Both the SyncActive pool and the
SyncAlternate pool must have
enough space for the volume and
snapshot reserve.
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